Sorry for your loss! I posted something similar though different earlier, and I understand what you mean. It is so tough to lose someone you love to such a disease also, instead of a "natural passing". You will get through the days, but it will be some days where Its hard to even stand up from bed and function. From personal experience, try to accept those feelings and be okay with days that you know "is one of those days". or even periods of days.
I can not imagine how it is losing a parent, but.. I know the feeling of loss. Take care, and things will get better, trust me.